Manage shared libraries
Overview
Shared libraries are files used by multiple applications. Each shared library consists of...
- A symbolic name
- A Java class path
- A native path for loading JNI libraries
You can use shared libraries to reduce the number of duplicate library files on your system.
Suppose that you have four applications that use the same library file, mysample.jar. Instead of having four copies of mysample.jar on your system after the four applications are deployed, you can define a shared library for mysample.jar and have the four deployed applications use that one mysample.jar library file.
Using the console, you can define a shared library.
On a single-server product, you can define a shared library at the cell, node, or server level.
On a multiple-server product, you can define a shared library at the cell, node, server, or cluster level.
A separate class loader is used for shared libraries that are associated with an appserver. This class loader is the parent of the application class loader, and the WAS extensions class loader is its parent. Shared libraries that are associated with an application are loaded by the application class loader.
Defining a library at one of the these levels does not automatically place the library into the class loader for an appserver. You must associate the library to an application or server before the classes represented by the shared library are loaded into either a server-wide or application-specific class loader.
Using the console, you can then associate the library with an application, module, or server to load the classes represented by the shared library in either a server-wide or application-specific class loader.
Using an installed optional package, you can associate a shared library to an application by declaring the dependent library .jar file in the MANIFEST.MF file of the application. Refer to the J2EE 1.4 specification, section 8.2 for an example.
If your deployed applications use shared library files, define shared libraries for the library files and associate the libraries with specific applications or modules or with an appserver. Associating a shared library file with a server associates the file with all applications on the server. Use the Shared Libraries page to define new shared library files to the system and to remove existing library files from the system.
Procedures
- Use the console to define a shared library.
- Create a shared library for each library file that your applications need.
- Associate each shared library with an application or module.
- Associate a shared library with an application or module that uses the shared library file.
- Associate a shared library with an appserver so every application on the server can use the shared library file.
- Use an installed optional package to declare a shared library for an application.
- Remove a shared library.
- Click...
Environment | Shared Libraries...in the console navigation tree to access the Shared Libraries page.
- Select the library to be removed.
- Click Delete.
The list of shared libraries is refreshed. The library file no longer displays in the list.
Create shared libraries
Shared library collection
Associate shared libraries with applications or modules
Associate shared libraries with servers
Installed optional packages
Use installed optional packages
Library reference collection
Related concepts
Class loaders
Related tasks
Configure native libraries in shared libraries
Related Reference
Shared library settings